In prior art code division multiple access (CDMA) systems utilizing closed loop transmit diversity (CLTD), base stations having multiple antennas use an antenna weight coefficient vector to adjust the phase and/or relative amplitude of signals transmitted from each antenna. In such systems, a mobile station computes a set of optimized antenna weight coefficients that should be applied at the base station antennas to maximize the mobile received signal power. The mobile station then feeds back to the base station a set of antenna control bits for use by the base station in generating the optimized antenna weights. In prior art CLTD systems, the antenna control bits are sent in an unencoded (i.e., a single bit per time slot with no redundancy bits) feedback message, which creates a number of problems. For example, because there are no redundancy bits, the feedback message must be transmitted at a high power to ensure a low error rate, which may result in reduced battery life and increased interference. Because a single bit is transmitted per time slot, transmitting multiple antenna control bits may also result in an unacceptable feedback delay.
The mobile station also feeds back a channel quality indication (CQI) for use by the base station in transmissions scheduling and transport format (TF) selection (i.e., the number of data bits and redundancy bits to send in a time slot). In prior art CLTD systems, the antenna control bits and channel quality indication are fed back to the base station over separate channels, each requiring separate spreading codes and processing overhead.